Diagnostic assays based upon multiple biomarkers have been used on only a limited basis. For example, assays have been proposed in which gene expression is measured in several genes in order to assess clinical status. Also, multiple protein analytes have been used to screen for the presence of any of multiple disorders when diagnosis is unclear. Generally, algorithms are used in order to assess the results of any standard assay and, in particular to assess whether additional testing is needed. However, since different biomarker types provide different informative results, most assays have been limited to a single marker or analyte per condition to be screened.
It is common to screen multiple analytes from the same sample for different clinical indications. This is especially true when a patient presents with ambiguous symptoms. For example, a single blood sample may be screened for hematocrit, hepatitis antigen, HIV, and SARS. Each of those screens, however, is directed to a different clinical condition and is tied into a different algorithm to produce separate results for each of the clinical indications that the marker is intended to measure. Such a broad screen is used to rule out or rule in one or more diagnostic pathways in a situation in which diagnosis is ambiguous or difficult.
Increasing the number of biomarkers in any screening assay increases the accuracy of diagnosis. However, there is no assay that allows the screening and/or diagnosis of a condition based upon a plurality of biomarkers. Therefore, there is a need in the art for assays and diagnostic algorithms that allow screening and diagnosis of a condition based upon multiple biomarkers.